初学者,
代码如下:
package frame;
import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
public class Sketch{
public static void main(String[] args)
{
SketchFrame frame=new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}
class SketchFrame extends JFrame{
public SketchFrame(){
setTitle("键盘事件");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
SketchPanel panel=new SketchPanel();
Container contentPane=getContentPane();
contentPane.add(panel);
}
public static final int DEFAULT_WIDTH=300;
public static final int DEFAULT_HEIGHT=200;
}
class SketchPanel extends JPanel
{
public SketchPanel()
{
last=new Point2D.Double(100,100);
lines=new ArrayList();
KeyHandler listener=new KeyHandler();
addKeyListener(listener);
setFocusable(true);
}
//添加坐标
public void add(int dx,int dy)
{
Point2D end=new Point2D.Double(last.getX()+dx,last.getY()+dy);
Line2D line=new Line2D.Double(last,end);
lines.add(line);
repaint();
last=end;
}
//画图方法
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g;
for(int i=0;i<lines.size();i++)
{
g2.draw((Line2D)lines.get(i));
}
}
private Point2D last;
private ArrayList lines;
private static final int INCREMENT=10;
private class KeyHandler implements KeyListener
{
public void keyPressed(KeyEvent event)
{
int keyCode=event.getKeyCode();
int d;
d=INCREMENT;
if(keyCode==KeyEvent.VK_LEFT) add(-d,0);
else if (keyCode==KeyEvent.VK_RIGHT) add(d,0);
else if (keyCode==KeyEvent.VK_UP) add(0,-d);
else if (keyCode==KeyEvent.VK_DOWN) add(0,d);
}
public void keyReleased(KeyEvent event){}
public void keyTyped(KeyEvent event)
{
char keyChar=event.getKeyChar();
int d;
if (Character.isUpperCase(keyChar))
{
d=INCREMENT;
keyChar=Character.toLowerCase(keyChar);
}
else
d=INCREMENT;
if (keyChar=='h') add(-d,0);
else if (keyChar=='I') add(d,0);
else if (keyChar=='k') add(0,-d);
else if (keyChar=='j') add(0,d);
}
}
}编译过不去,请高手解答原因,谢谢。
代码如下:
package frame;
import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
public class Sketch{
public static void main(String[] args)
{
SketchFrame frame=new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}
class SketchFrame extends JFrame{
public SketchFrame(){
setTitle("键盘事件");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
SketchPanel panel=new SketchPanel();
Container contentPane=getContentPane();
contentPane.add(panel);
}
public static final int DEFAULT_WIDTH=300;
public static final int DEFAULT_HEIGHT=200;
}
class SketchPanel extends JPanel
{
public SketchPanel()
{
last=new Point2D.Double(100,100);
lines=new ArrayList();
KeyHandler listener=new KeyHandler();
addKeyListener(listener);
setFocusable(true);
}
//添加坐标
public void add(int dx,int dy)
{
Point2D end=new Point2D.Double(last.getX()+dx,last.getY()+dy);
Line2D line=new Line2D.Double(last,end);
lines.add(line);
repaint();
last=end;
}
//画图方法
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g;
for(int i=0;i<lines.size();i++)
{
g2.draw((Line2D)lines.get(i));
}
}
private Point2D last;
private ArrayList lines;
private static final int INCREMENT=10;
private class KeyHandler implements KeyListener
{
public void keyPressed(KeyEvent event)
{
int keyCode=event.getKeyCode();
int d;
d=INCREMENT;
if(keyCode==KeyEvent.VK_LEFT) add(-d,0);
else if (keyCode==KeyEvent.VK_RIGHT) add(d,0);
else if (keyCode==KeyEvent.VK_UP) add(0,-d);
else if (keyCode==KeyEvent.VK_DOWN) add(0,d);
}
public void keyReleased(KeyEvent event){}
public void keyTyped(KeyEvent event)
{
char keyChar=event.getKeyChar();
int d;
if (Character.isUpperCase(keyChar))
{
d=INCREMENT;
keyChar=Character.toLowerCase(keyChar);
}
else
d=INCREMENT;
if (keyChar=='h') add(-d,0);
else if (keyChar=='I') add(d,0);
else if (keyChar=='k') add(0,-d);
else if (keyChar=='j') add(0,d);
}
}
}编译过不去,请高手解答原因,谢谢。
请将
main方法中的frame.show();
替换为
frame.setVisible(true);
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
public class Sketch{
public static void main(String[] args) {
SketchFrame frame=new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true); //******这里改了
}
} class SketchFrame extends JFrame{
public SketchFrame(){
setTitle("键盘事件");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
SketchPanel panel=new SketchPanel();
Container contentPane=getContentPane();
contentPane.add(panel);
}
public static final int DEFAULT_WIDTH=300;
public static final int DEFAULT_HEIGHT=200;
} class SketchPanel extends JPanel {
public SketchPanel() {
last=new Point2D.Double(100,100);
lines=new ArrayList<Line2D>(); //******这里改了
KeyHandler listener=new KeyHandler();
addKeyListener(listener);
setFocusable(true);
}
//添加坐标
public void add(int dx,int dy) {
Point2D end=new Point2D.Double(last.getX()+dx,last.getY()+dy);
Line2D line=new Line2D.Double(last,end);
lines.add(line);
repaint();
last=end;
}
//画图方法
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g;
for(int i=0;i <lines.size();i++) {
g2.draw((Line2D)lines.get(i));
}
}
private Point2D last;
private ArrayList<Line2D> lines; //******这里也改了
private static final int INCREMENT=10;
private class KeyHandler implements KeyListener {
public void keyPressed(KeyEvent event) {
int keyCode=event.getKeyCode();
int d;
d=INCREMENT;
if(keyCode==KeyEvent.VK_LEFT) add(-d,0);
else if (keyCode==KeyEvent.VK_RIGHT) add(d,0);
else if (keyCode==KeyEvent.VK_UP) add(0,-d);
else if (keyCode==KeyEvent.VK_DOWN) add(0,d);
}
public void keyReleased(KeyEvent event){}
public void keyTyped(KeyEvent event) {
char keyChar=event.getKeyChar();
int d;
if (Character.isUpperCase(keyChar)) {
d=INCREMENT;
keyChar=Character.toLowerCase(keyChar);
} else
d=INCREMENT;
if (keyChar=='h') add(-d,0);
else if (keyChar=='I') add(d,0);
else if (keyChar=='k') add(0,-d);
else if (keyChar=='j') add(0,d);
}
}
}是要做贫吃蛇么?